Hm. Stein et al., EFFECT OF CORTICOSTEROIDS ON FREE AND SULFOCONJUGATED CATECHOLAMINES AT BIRTH IN PREMATURE NEWBORN SHEEP, American journal of physiology: endocrinology and metabolism, 31(1), 1995, pp. 28-32
We previously demonstrated that prenatal corticosteroids attenuated th
e expected exponential increase in circulating catecholamines at birth
. The present studies were undertaken to determine if alteration in su
lfoconjugation could account for this attenuation. Catheterized fetal
lambs received saline (n = 6) or corticosteroids (n = 8) intravenously
for 60 h. The lambs were delivered by cesarean section at 130 +/- 1 d
ays gestation. Ventilatory and cardiovascular responses and plasma cat
echolamine concentrations were measured for 2 h after birth. Although
plasma free catecholamines levels were higher in controls than in cort
icosteroid-treated fetuses, the sulfoconjugated levels were similar in
the two groups. Thus the corticosteroid-treated fetuses had a higher
proportion of plasma sulfoconjugated catecholamines consistent with th
e possibility that sulfoconjugation was augmented during intrauterine
life. After birth, the corticosteroid-treated animals showed an attenu
ated increase in plasma free catecholamine levels compared with contro
ls but a similar increase in sulfoconjugated catecholamine levels to t
he control animals. The proportion of plasma sulfoconjugated catechola
mines was higher in the corticosteroid-treated animals; however, the i
ncrease in sulfoconjugated catecholamines was insufficient to account
for the attenuated overall increase in total catecholamines in the cor
ticosteroid-treated animals.